Latex allergy represents a real problem of public health worldwide, and, despite multiple efforts to solve this situation, no other substitute material having the same characteristics that made latex a successful product has been discovered to date. However, thanks to biotechnology based on surface chemistry and microfilm technology, the present invention succeeds in providing a solution to this condition.
The latex products industry uses about 4.5 million tons of latex per year (5). This material is used in the manufacture of rubber pumps, condoms, electrical materials, gloves and other products for medical use. This polymer is related to many daily activities of health personnel, especially when using gloves or disposable medical materials (1, 2)
Latex is the second most common cause of anaphylactic reaction in operating rooms (16.6% of cases). However, the incidence has declined in response to the identification of patients at risk, improvements in laboratory determinations, and introduction of measures for the prevention and reduction of latex in many medical products.
The prevalence of sensitization to latex is less than 1% in the normal population without atopy, but in health personnel it fluctuates between 3 and 12%. (6, 9, 11)
Using the determination of IgE in serum (specific against latex), 4-6.4% of individuals are positive (14). The incidence of latex sensitization (measured as a level of specific IgE) in ambulatory surgical patients is 6.7% (9). The prevalence of latex allergy in the general population is 0.7-11%. (15)
In a group of non-sensitized individuals who began to work in health, it was demonstrated that there was a 6.4% cumulative incidence of skin sensitivity, 1.8% for people with rhinoconjunctivitis, and 4, 5% for those with occupational asthma. (21)
High-risk latex allergy groups include: health workers, workers with occupational exposure to latex (police officers, stylists, food handlers), individuals with a history of atopy, and patients with spina bifida and genitourinary abnormalities requiring multiple surgical interventions. (9, 11, 16, 17)
Patients with spina bifida, even without multiple surgeries, are at increased risk. The most frequent manifestation in spina bifida is urticaria (8, 9, 18, 22). Obojski (23) reported respectively 32.4% and 18.8% prevalences in boys and girls when sensitized and suffering from allergy to latex. In children with spina bifida and congenital diseases requiring multiple surgeries, the frequency is reported to be between 23-70% (10, 17, 18, 22).
Health workers are the main risk group due to constant exposure to latex products; the frequency of sensitization in the hospital population fluctuates between 2.8-17%. In other occupations with latex exposure, the frequency ranges from 5-11%. Allergy in health workers with latex allergy is 2.2-4.2 times more frequent than in control workers. In adults with latex allergy, a prevalence of up to 82% is reported (17). A health worker who is atopic has an increased risk of sensitization and allergy to latex.
Anesthesiologists have a 12.5% and 2.4% prevalence of sensitization and allergy to latex respectively (23). Anesthesiologists treating adults change their gloves more often than those treating children and have a higher sensitivity to latex, those affected being estimated to be 24%. (9, 24)
Although the latex industry has tried to solve the problem of allergies, this has not been achieved by any technique, including: talc treatment, multiple washes, chlorination, hydrogel treatments, PVC gloves, neoprene gloves, Styrene block copolymer gloves, and even polyurethane gloves. But none of these managed to even lessen the problem.
The other materials that are currently available have not been able to reproduce the main benefits of latex, which are price, sensitivity, durability, and memory that keeps the gloves shape when they stretch, even with the most demanding maneuvers.
Latex protein: Natural latex is a milky liquid from the Hevea Brasiliensis tree. Its matrix contains soluble and insoluble proteins. These proteins are subjected to hydrolysis and denaturation during the manufacturing process. The latex particles are insoluble in water, but the presence of ammonium that is used to stabilize them and preserve them increases their solubility. The ammonium breaks the organelles present in the latex and releases the soluble material. Fragments of the proteins give rise to low molecular weight polypeptides. About 240 different polypeptides have been detected in the ammoniated latex, with molecular mass between 5-200 kd. However, only 25% of these peptides, with molecular mass between 5-100 kd, show ligation with IgE of the serum of patients with latex allergy. (7, 9, 11)
The main allergen in the latex is the rubber elongation factor (Hev b). There are 11 Hev b proteins (Hev b1 to Hev b11) within these Hev b5 (18-20 kd) or latex profilin and Hev b6.02 (4.7 kd) hevein. Sensitization to Hev b5 is common in the health worker group. The concentration of Hev b1 in natural rubber products is reported to be between 18-40 mg/g, corresponding to 2-4% of extractable total protein in the gloves. Hev b6.02 and Hev b5 are responsible for most latex allergens in medical gloves. (9, 11, 12, 15, 17, 25)
Latex allergens interact with carbohydrates. These allergens, such as Hev b6.01, Hev b6.02 and Hev b11, are bound to oligosaccharides of N acetylglucosamine thanks to a hevein domain. This type of domain has also been described in other plants, notably Pers a 1 (avocado), and some others present in banana, kiwi and chestnut, which could explain the fact that people sensitive to latex are also sensitive to these fruits. (20)
Corn starch, used as a powder to lubricate gloves, acts as an allergen transporter when linked to latex proteins. When the particles are aerolized upon use of the gloves, exposure to latex occurs in all individuals in the area. (13) Corn starch powder adheres to latex particles and acts as a carrier. Talc (magnesium silicate) is capable of binding latex particles, however the union is irreversible as they cannot release the latex to the environment and it is a bad aeroallergen transporter for being heavier.
Another exposure route is the one that occurs when the allergens of the latex come into contact with the tissues and mucous membranes of the patient during surgical, dental or medical procedures. (13)
Sensitivity to latex: In the molecular structure of allergenic proteins, there are immunodominant regions, called epitopes, which interact with the antigen-binding fragments (Fab) of the specific IgE antibodies. Fab-allergen immune complexes have between 15 and 22 amino acid residues. Of these, only 3 to 5 residues contribute to the binding process through multiple non-covalent complementary bonds, originated by electrostatic forces, mainly Van der Waals type. (19)
Patients with latex sensitivity have an altered humoral and cellular immune response, which facilitates the reaction with environmental antigens.
Increase of serum IgE: In 80% of the cases, IgE is capable of mediating an immediate, but also a late, immunological response (FIG. 1). (20)
Surface Chemistry can be more or less defined as the study of chemical reactions at interfaces. It is closely related to surface engineering, whose purpose is to modify the chemical composition of a surface by incorporating certain elements or functional groups that produce various desired effects or improvements in the properties of the surface or interface. Surface Chemistry also overlaps with electrochemistry. Surface science is of particular importance for the field of heterogeneous catalysis.
The adhesion of the gas or liquid molecules to the surface is known as adsorption. This may be due to chemical absorption or porphyrosorption. These are also included in Surface Chemistry.
The behavior of a solution based on the interface is affected by the surface charge, dipoles, energies, and their distribution within the double electric layer.
Surface Chemistry develops and offers superior low cost products formulated for the preparation of specialized surfaces and difficult surface cleaning applications. These new chemicals are used in the preparation and manufacture of high technology devices; however, their usefulness also extends to cleaning industrial surfaces and preparation. Chemical surface discoveries can help achieve the most effective surface preparation, textures and cleaning needs of the solar cell and the manufacture of semiconductors.
Surface Chemistry consists of the study of the physical and chemical processes that take place in the interfaces of the different habitual states of matter: solids, liquids and gases. That is, it deals with the contact zones between the different states of matter or phases where a set of atoms, small in quantity of species in comparison with the total of atoms and molecules that constitute the phases, interacts and form new chemical species. Therefore, Surface Chemistry must cover the basic concepts of Solid State Chemistry and Coordination Chemistry.
The interest of Surface Chemistry, as an interdisciplinary field of investigation, lies in the multiple applications and consequences derived from the processes that take place on surfaces, among which we can mention: electrochemical reactions, colloidal systems, detergency and flotation, biological membranes, lubrication, corrosion, heterogeneous catalysis, etc. Limiting us to the application of the concepts of Surface Chemistry in Heterogeneous Catalysis, we must remember several key facts in relation to history and industrial applications. Thus, it is revealing that, in the third decade of the nineteenth century, when J. J. Berzelius or M. Faraday began to write about the phenomenon of “catalysis”, they referred to a previous patent of 1831 consisting of a heterogeneous catalytic process, the manufacture of sulfuric acid.
No less important is another development of catalysts, this one from the beginning of the 20th century, which facilitated the ammonia synthesis using atmospheric nitrogen as reagent. This industrial process made possible the production of fertilizers and the advent of modern agriculture, which, among other things, made it possible to feed an exponentially growing world population over the past century. We could delve into how the oil derivatives industry, based on various catalytic processes, has helped in the expansion of automotive or aviation use.
Also, the plastics, produced with polymerization catalysts of organic compounds, are now present in all the materials that surround us. And from all this we can conclude that catalysis, and therefore Surface Chemistry, can be considered as technological pillars of the chemical industry and as key concepts in the resolution of new environmental and energetic problems. From a final point of view, Surface Chemistry and its heterogeneous catalysis are present in new industrial and technological developments ranging from the production of hydrogen or the transformation of biomass to photocatalysis, through fundamental operations to achieve a more sustainable chemical industry (Green Chemistry). The research situation in Surface Chemistry is exciting.
The emergence of new techniques of study, the evolution of experimental analytical methods and the support of computational methods have meant going from mere speculations about the nature of the surface centers where a process or reaction takes place to being able to achieve a rational design of the synthesis of the catalytically active material (we would now call it nanomaterial). As for the challenges applied, catalytic reactions leading to enantiomers may have special appeal, since they require atomic-scale control of both the surface of the catalyst and the intermediate species that are being produced; that is, of the intermediates chemisorbed or bound to the surface site with chiral specificity.
From the point of view of the deep knowledge of the reactions that occur on a surface, we must emphasize the development of the techniques with temporal resolution in the detection of the chemical changes, that is to say those that allow us to follow the intermediates present in the surface for periods of the order of the microsecond (10-6 seconds) up to the PS (10-12 seconds) depending on the life span of the species and the concrete reaction studied.
By way of example, we can indicate the spectroscopies of absorption of X-rays capable of giving rise to spectra in a few microseconds. It is also necessary to mention the studies that are carried out using isotopically labeled compounds, in particular if they are operated in the modern Temporal Analysis of Products (TAP) reactors. Many of these experimental techniques are performed “in situ”, that is, while studying the chemistry under the conditions of the reaction that is taking place.